EMTB brake noise solutions? Is this normal?

[Dallant]

My new Rail 5 is an almost perfect ebike with only about 35 miles on it. I’ve been dealing with an irritating raspy noise from the front brake since the day I bought it. It’s very infrequent, sometimes loud, sometimes non-existent, and it happens even when I’m coasting along a perfect paved path without operating the brakes at all. There’s no specific rhythm to the noise. Brakes have been adjusted by Trek techs and they’ve reduced it but it is still annoyingly loud at times. I find it impossible to believe it’s normal and the brakes appear to be bedded in correctly. Thoughts?

 

[fooferdoggie]

My new Rail 5 is an almost perfect ebike with only about 35 miles on it. I’ve been dealing with an irritating raspy noise from the front brake since the day I bought it. It’s very infrequent, sometimes loud, sometimes non-existent, and it happens even when I’m coasting along a perfect paved path without operating the brakes at all. There’s no specific rhythm to the noise. Brakes have been adjusted by Trek techs and they’ve reduced it but it is still annoyingly loud at times. I find it impossible to believe it’s normal and the brakes appear to be bedded in correctly. Thoughts?

the rotor can warp after use then straight out again. I get this a lot on the tandem. sometimes randomly.

 

[Dallant]

I didn't know what Rail 5 was, so I looked it up and learned that it was a Trek eMTB.
It has Tektro HD-M745, which comes with either one of these pads.

Sintered Pad

1TEKTRO BRAKE SYSTEMS - Products

TEKTRO BRAKE SYSTEMS - Product, Disc, Brake, Lever, Disc Pads, Brake Pads, Accessories, MTB Road, Cyclocross, TT / Triathlon, Recreation, BMX, E-Bike.

www.tektro.com

Metallic Compound Pad

1TEKTRO BRAKE SYSTEMS - Products

TEKTRO BRAKE SYSTEMS - Product, Disc, Brake, Lever, Disc Pads, Brake Pads, Accessories, MTB Road, Cyclocross, TT / Triathlon, Recreation, BMX, E-Bike.

www.tektro.com

Assuming everything is adjusted right, it could be the pad.
Sintered pads (or metallic and semi-metallic for that matter) are very loud.

Professional MTB racers don't care about the noise, since all they care about is brake performance, but to a daily commuter like me, I absolutely hate the noise of sintered pads.

I'd recommend you getting a Shimano resin pad instead.
You might also be able to find organic pads from Swiss Stop, etc.
It is much quieter, although the braking performance won't be as good as sintered pads, it gets the job done for daily commute and still works fine.

Y1XM98010

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bike.shimano.com

What annoys me the most is that the noises happen mostly when I’m not even touching the brake. Its my opinion that the rotor or the wheel is out of round but what do I know? I’m wanting Trek to replace whatever on warranty.

 

[fooferdoggie]

What annoys me the most is that the noises happen mostly when I’m not even touching the brake. Its my opinion that the rotor or the wheel is out of round but what do I know? I’m wanting Trek to replace whatever on warranty.

I would check how tight the qr is on the hub it may be too tight or not tight enough and causing flex.

 

[Stefan Mikes]

I would check how tight the qr is on the hub it may be too tight or not tight enough and causing flex.

He certainly has thru-axles in his wheels. Thru axle makes the brake rotor always stay in the same position disregarding the QR. No noise should be heard during the ride. My friend who recently bought a Rail 5 had the same issue. Eventually the rotor was replaced under warranty.

 

[BlackHand]

My Haibike has the same brakes and had similar noises from the front brakes when I first got it. Usually showed up in the middle of a ride sometime after using the brakes hard (could be 10 seconds or 10 minutes).

It disappeared after I carefully straightened the very slightly warped rotor and dealt with a somewhat sticky piston.

If you have the same size rotors on both wheels you might try swapping them to see if the noise moves with the rotor or persists at the front brakes.

 

[PDoz]

What annoys me the most is that the noises happen mostly when I’m not even touching the brake. Its my opinion that the rotor or the wheel is out of round but what do I know? I’m wanting Trek to replace whatever on warranty.

Spotting a bent rotor is easy - look at the gap between disc and pads whilst spinning the wheel.

Whilst you are there, is the gap even, eg does the disc get pushed to one side as you apply the brakes ( easy to adjust - loosen the allen head mounting bolts, apply brake, then tighten them with the brake still on / caliper now centralized ( if you need to do this several times , it's time to ask the lbs about a sticking piston)

Pull the pads out and check for gouges / dirt stuck , and whilst there check all the pistons are even

Other small print things:

Someone stuffed up when installing the pads - eg the retaining clip is bent and catching
brake lever adjusted too tight and not getting to fully release ( make sure you have dome free play)
Someone put the spacer on upside down ( the direction is printed on it, I think those have the wider bit at the top)

If all this doesn't help, try posting a video next time ( flip your bike uoside down, spin thd wheel, wave the phone around randomly)

 

[Dallant]

Spotting a bent rotor is easy - look at the gap between disc and pads whilst spinning the wheel.

Whilst you are there, is the gap even, eg does the disc get pushed to one side as you apply the brakes ( easy to adjust - loosen the allen head mounting bolts, apply brake, then tighten them with the brake still on / caliper now centralized ( if you need to do this several times , it's time to ask the lbs about a sticking piston)

Pull the pads out and check for gouges / dirt stuck , and whilst there check all the pistons are even

Other small print things:

Someone stuffed up when installing the pads - eg the retaining clip is bent and catching
brake lever adjusted too tight and not getting to fully release ( make sure you have dome free play)
Someone put the spacer on upside down ( the direction is printed on it, I think those have the wider bit at the top)

If all this doesn't help, try posting a video next time ( flip your bike uoside down, spin thd wheel, wave the phone around randomly)

I do think there’s a very minor bend to the rotor. I personally watched a Trek tech adjust the gap as you mention about three times. It helped but is still there. I’ll be calling the Trek shop to mention some of these other possibilities. I recordered the noise and will try to publish.
The bike never seems to make the noise without rider weight on it. Even then it didn’t make the noise when one Trek guy tried riding it to diagnose.

 

[Dallant]

I would check how tight the qr is on the hub it may be too tight or not tight enough and causing flex.

QR?

 

[PDoz]

QR?

Quick Release - remember the old wheels with a skewer that went through them? Irrelevant to your trek

 

[PDoz]

I do think there’s a very minor bend to the rotor. I personally watched a Trek tech adjust the gap as you mention about three times. It helped but is still there. I’ll be calling the Trek shop to mention some of these other possibilities. I recordered the noise and will try to publish.
The bike never seems to make the noise without rider weight on it. Even then it didn’t make the noise when one Trek guy tried riding it to diagnose.

If it took multiple adjustments there is possibly a sticking piston - pull the pads out, gently apply lever , one of them will be slower to move than the other 3. Show that to the shop .

nb only one squeeze of the lever - you don't want yo pop them out

 

[Dallant]

If it took multiple adjustments there is possibly a sticking piston - pull the pads out, gently apply lever , one of them will be slower to move than the other 3. Show that to the shop .

nb only one squeeze of the lever - you don't want yo pop them out

It’s still at a Trek shop. I want this to be documented work for possible future warranty reasons. I’m not touching these brakes as they are beyond my capabilities & tool collection.

 

[PDoz]

It’s still at a Trek shop. I want this to be documented work for possible future warranty reasons. I’m not touching these brakes as they are beyond my capabilities & tool collection.

Fair enough, that's the luxury of big brand support.

 

[Dallant]

Fair enough, that's the luxury of big brand support.

Not that I don’t wish to learn and improve my tool collection! I learn a lot on this site every day!

 

[PDoz]

Funny story.....aka don't dabble if in doubt.....or there are easy and hard ways to learn...

Last weekend I swapped my fox 34's for 36 (parts shuffle amongst the fleet). Would you believe fox 34's have a 20 mm different minimum rotor size to 36 ?

About halfway down a black run I was trying to work out why the brakes felt so weak...by the end of the run, the front wheel was almost locked up! My rotor is 200 mm , so the original 40 mm spacer puts the caliper 20 mm too far out - only half the pad was in contact, and as it wore the pistons started twisting / sticking!!!


PS - all the checks I suggested can be done with your bikes multi tool ( or 2 allen keys and possibly some needle nose pliers if there is a circlip on the retaining bolt for the pads) . New pads come with new circlips if it flues across the shed

 

[Dallant]

OK, just got a call from the Trek shop. They did take it for a ride, did hear the issue, did try adjusting spring tension on the piston and then when that worked but not completely, they called Tekro. Tekro admitted they’ve had this issue and are shipping a stronger replacement 203-53 rotor under warranty. Apparently Trek will do all this work under warranty. Hopefully they’ll get this in and finished by the end of the week and hopefully this fixes it!

 

[Dallant]

He certainly has thru-axles in his wheels. Thru axle makes the brake rotor always stay in the same position disregarding the QR. No noise should be heard during the ride. My friend who recently bought a Rail 5 had the same issue. Eventually the rotor was replaced under warranty.

So what rotor was your friend’s Rail 5 rotor replaced with? Is it still a successful replacement?

 

[Stefan Mikes]

So what rotor was your friend’s Rail 5 rotor replaced with? Is it still a successful replacement?

I can't remember details. It turned out the original rotor was unavailable. The Trek dealer is serious, so they brought a quality rotor of other brand from Germany (it is a fast process here) and replaced it under warranty. I can ask for details if you like Dallant. (My friend is very happy!)

 

[Dallant]

I can't remember details. It turned out the original rotor was unavailable. The Trek dealer is serious, so they brought a quality rotor of other brand from Germany (it is a fast process here) and replaced it under warranty. I can ask for details if you like Dallant. (My friend is very happy!)

Glad to hear he’s happy! It’s no big deal, I was just curious as Tekro is evidently sending a Tekro 203-53 replacement rotor in 2-3 business days. I’ll believe that delivery date when I see it. I’m very happy other than the irritating noise as the brakes (as everything else) work very well.

 

[Stefan Mikes]

Glad to hear he’s happy! It’s no big deal, I was just curious as Tekro is evidently sending a Tekro 203-53 replacement rotor in 2-3 business days. I’ll believe that delivery date when I see it. I’m very happy other than the irritating noise as the brakes (as everything else) work very well.

His rotor was replaced with Shimano sm-rt86m 180mm. Just to let you know.